The first member of the diamondoid family of molecules is adamantane. Adamantane, tricyclo-[3.3.3.1.sup.3,7 ]decane, is a polycyclic alkane with the structure of three fused cyclohexane rings. The ten carbon atoms which define the framework structure of adamantane are arranged in an essentially strainless manner. Four of these carbon atoms, the bridgehead carbons, are tetrahedrally disposed about the center of the molecule. The other six (methylene carbons) are octahedrally disposed. The octahedral disposition of the methylene carbons in adamantane is discussed at length in commonly assigned U.S. Application Ser. No. 426,609, filed Oct. 25, 1989, the disclosure of which is incorporated by reference as if set forth at length herein. For a general survey of the chemistry of diamondoid molecules, see Adamantane, The Chemistry of Diamond Molecules, Raymond C. Fort, Marcel Dekker, N.Y., 1976.
Adamantane is the smallest member of the group referred to herein as diamondoid molecules. The larger diamondoid molecules such as diamantane and triamantane also contain methylene carbons; however, the methylene carbons in these higher adamantalogs exhibit non-octahedral geometries with respect to the center of the molecule. While not presented to limit the scope of the present invention by a recitation of theory, the unusual chemical and physical properties exhibited by higher adamantalog polymers of the present invention may be explained at least in part by the geometry of double bonds extending through the methylene groups.
Diamondoid compounds have been found to be useful building blocks in the synthesis of a broad range of organic compounds, as exemplified by the following references.
U.S. Pat. No. 3,457,318 to Capaldi et al. teaches the preparations of polymers of alkenyl adamantanes and alkenyl adamantanes useful as coatings, electrical appliance housings, and transformer insulation. The process, yielding polymers bonded through the tetrahedral bridgehead carbons, comprises contacting an adamantyl halide in the presence of a suitable catalyst with a material selected from the group consisting of substituted allyl halides and olefins to produce adamantyl dihaloalkanes or adamantyl haloalkanes as an intermediate product. The intermediate product is then dehalogenated or dehydrogalogenated, respectively, to produce the alkenyl adamantane final product.
U.S. Pat. No. 3,560,578 to Schneider teaches the reaction of adamantane or alkyladamantanes with a C.sub.3 -C.sub.4 alkyl chloride or bromide using AlCl.sub.3 or AlBr.sub.3 as the catalyst. The reference describes polymerization through C.sub.3 -C.sub.4 linkages connecting bridgehead carbon atoms in the starting adamantane hydrocarbon via single carbon-carbon bonds; See column 3, lines 35-55, as well as the structural illustrations in columns 3-5.
U.S. Pat. No. 3,580,964 to Driscoll discloses polyesters containing hydrocarbyladamantane moieties as well as novel intermediate diesters and crosslinked polymers prepared therefrom. The hydrocarbyladamantane moieties are bonded through single bonds connecting the tetrahedral bridgehead carbons; See column 2, lines 6-46 and the diesters illustrated in column 3, lines 55-75.
U.S. Pat. No. 3,639,362 to Dulling et al. discloses novel copolymers having low mold shrinkage properties which are prepared from adamantane acrylate and methacrylates. The adamantane molecule is bonded to the polymer chain through single bonds linking the tetrahedral bridgehead carbon atoms.
U.S. Pat. No. 3,649,702 to Pincock et al. discloses a reactive derivative of adamantane, 1,3 dehydroadamantane. The reference shows bridgehead substituents including halogens and alkyls; See column 1, lines 45-64.
U.S. Pat. No. 3,748,359 to Thompson teaches the preparation of an alkyladamantane diamine from an alkyladamantane diacid. The diamine product is illustrated at column 1, lines 20-30, clearly showing single bonding through the bridgehead carbons.
U.S. Pat. No. 3,832,332 to Thompson teaches a polyamide polymer prepared from an alkyladamantane diamine. As discussed and illustrated in the Thompson '332 patent at column 2, lines 41-53, the polymer comprises repeating units which include the backbone structure of adamantane. Note that the adamantane structure is bonded to the polymer chain through single bonds extending from the bridgehead positions.
U.S. Pat. No. 3,966,624 to Duling et al. teaches a power transmission fluid containing a saturated adamantane compound. The adamantane compound consists of adamantane-like structures connected through ester linkages, ether linkages, carboxylic acids, hydroxyl or carbonyl groups; See the Abstract as well as column 1, line 49 through column 2, line 50.
U.S. Pat. No. 3,976,665 to Feinstein et al. discloses a dianhydride containing an adamantane group bonded through single bonds at the bridgehead carbons.
U.S. Pat. No. 4,082,723 to Mayer et al. discloses aza-adamantane compounds for stabilizing polymers to retard degradation by light and heat. The compounds have an adamantane backbone structure with at least one bridgehead carbon replaced by nitrogen. Specified bridgehead carbons may also be replaced by phosphorus, a phosphoryl or thiophosphoryl group, or a methine group optionally substituted by a phenyl or methyl group; See column 1, line 4 through column 2, line 16. While the Mayer et al. patent teaches replacement of a methylene carbon with nitrogen attached to a substituent group, the reference neither teaches nor suggests polymerizing monomers comprising diamantane and the higher adamantalogs through double bonds at the methylene positions.
U.S. Pat. No. 4,142,036 to Feinstein et al. discloses adamantane compounds having 2 to 4 bridgehead positions substituted with phenylacyl moieties suitable for producing polymers useful for forming shaped objects such as film, fiber, and molded parts The ester-substituted adamantanes are also suitable as plasticizers for polyvinylchloride and other polymers. The Feinstein et al. '036 patent notes that the four bridgehead carbons are equivalent to each other and are also more susecptible to attack than the secondary carbons. Accordingly, the adamantane component of the polymer taught in Feinstein et al. '036 is bonded through single bonds extending from the tetrahedrally disposed bridgehead carbons.
U.S. Pat. No. 4,168,260 to Weizer et al. teaches nitrogen-substituted triaza-adamantanyl ureas useful as stabilizers for thermoplastic materials. Nitrogen replaces carbon in three of the four bridgehead positions.
U.S. Pat. No. 4,332,964 to Bellmann et al. discloses diacrylate and dimethacrylate esters containing bridegehead substituted adamantane monomers. The polymer synthesis technique disclosed at column 3, line 62 through column 7, line 61 includes halogen addition at bridgehead carbons followed by replacement of the halogen with the selected link of the polymer chain.